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GIS Tutorial 1

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... manipulate, and produce output data sets. Often use multiple data sets. GIS TUTORIAL 1 ... Output features (CBD streets) GIS TUTORIAL 1 - Basic Workbook. Clip ... – PowerPoint PPT presentation

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Title: GIS Tutorial 1


1
GIS Tutorial 1
  • Lecture 8
  • Spatial Data Processing

2
Outline
  • Attribute extraction
  • Feature location extraction
  • Location proximities
  • Geoprocessing tools
  • Model builder

3
Attribute extraction
  • Lecture 8

4
Attribute query extraction
  • You have tracts for an
  • entire state, but want
  • tracts for one county
  • only

5
Attribute query extraction
  • Select tracts by County FIPS ID
  • Cook County 031

6
Attribute query extraction
  • Cook County tracts selected
  • Export to new feature class or shapefile

7
Export selected features
  • Right-click to export selected features

8
Add new layer
  • Cook County tracts

9
Feature location extraction
  • Lecture 8

10
Select by location
  • Powerful function unique to GIS
  • Identify spatial relationships between layers
  • Finds features that are within another layer

11
Select by location
  • Have Cook County census tracts but want City of
    Chicago only
  • Cant use Select By Attributes
  • No attribute for Chicago
  • Use Municipality layer
  • City Chicago is a municipality within Cook County

12
Select by location
  • Select Chicago from municipalities layer

13
Select by location
  • Selection, Select By location

14
Export selected features
15
location proximities
  • Lecture 8

16
Points near polygons
  • Health officials want to know polluting companies
    near water features

17
Points near points
  • School officials want to know what schools are
    near polluting companies

18
Polygons intersecting lines
  • Transportation planner wants to know what
    neighborhoods are affected by construction
    project on major highway

19
Lines intersecting polygons
  • Public works official wants to know what streets
    or sidewalks will be affected by potential floods

20
Polygons completely within polygons
  • City planners want to know what buildings are
    completely within a zoning area.

21
Geoprocessing tools
  • Lecture 8

22
Geoprocessing overview
  • GIS operations to manipulate data
  • Typically take input data sets, manipulate, and
    produce output data sets
  • Often use multiple data sets

23
Common geoprocessing tools
  • Analysis
  • Extract Clip
  • Overlay intersect and union
  • Data management
  • Generalization - dissolve
  • General
  • Append
  • Merge

24
Accessing tools
  • Geoprocessing menu

25
Accessing tools
  • ArcToolbox

26
Accessing tools
  • Search window

27
Clip
  • Acts like a cookie cutter to create a subset of
    features

Clip features (Central Business District)
Input features (streets)
Output features (CBD streets)
28
Clip
29
Clip vs select by location
  • Clip
  • Clean edges
  • Looks good
  • Select by location
  • Dangling edges
  • Better for geocoding

30
Dissolve
  • Combines adjacent polygons to create new, larger
    polygons
  • Uses common field value to remove interior lines
    within each polygon, forming the new polygons
  • Aggregate (sums) data while dissolving

31
Dissolve
  • Create regions using U.S. states
  • Use SUB_REGION field to dissolve
  • Sum population

32
Dissolve
33
Dissolve results
  • States dissolved to form regions
  • Population summed for each region

34
Append
  • Appends one or more data sets into an existing
    data set
  • Features must be of the same type
  • Input datasets may overlap one another and/or the
    target dataset
  • TEST option field definitions of the feature
    classes must be the same and in the same order
    for all appended features
  • NO TEST option Input features schemas do not
    have to match the target feature classes's schema

35
Append
  • DuPage and Cook County are combining public works
    and need a new single street centerline file.

36
Append
  • Append will add DuPage streets to Cook County
    streets

37
Resultant layer
  • One street layer (Cook County) with all records
    and field items

38
Merge
  • Combines multiple input datasets of the same data
    type into a single, new output dataset
  • Illinois campaign manager needs a single voting
    district map but wants to preserve the original
    layers

39
Merge
40
Resultant layer
  • New voting district layer

41
Union
  • Overlays two polygon layers
  • Resulting output layer has combined attribute
    data of the two inputs
  • Contains all the polygons from the inputs,
    whether or not they overlap

42
Union
  • Neighborhoods and ZIP Codes

43
Union
44
Union
  • Better describes characteristics of a
    neighborhood.
  • Central business district 15222 vs 15219

45
Union
  • Attributes tables contain different fields and
    data

46
Union results
  • New polygons with combined data

47
Intersect
  • Computes a geometric intersection of the Input
    Features
  • Features (or portions of features which overlap
    in all layers and/or feature classes) will be
    written to the Output Feature Class
  • Inputs can have different geometry types

48
Intersect
  • City manager needs to know what buildings
    intersect flood zones and wants the flood data
    attached to each intersecting building

49
Intersect
50
Intersect result
  • Only building polygons that intersect flood zones
    with combined data fields

51
Model builder
  • Lecture 8

52
Model builder overview
  • Workflow processes can be complicated
  • Models automate and string functions together
  • Example
  • You have census tracts for a county and want to
    create neighborhoods for a city
  • Many steps are needed to create neighborhoods
    (join, dissolve, etc)

53
Starting map
  • TIGER census tracts and municipalities

54
Final map
  • Tracts dissolved to create neighborhoods

55
Crosswalk table
  • Neighborhood names are not included with the
    census tracts, so a crosswalk table was created
    with the name of neighborhood for each census
    tract
  • Some neighborhoods are made of multiple tracts

56
Set geoprocessing options
  • Geoprocessing, geoprocessing options

57
Create a new toolbox
  • Catalog

58
Create a new model
  • Right-click new Toolbox

59
Add tool to model
  • Add Join Tool
  • To join crosswalk table to tracts

60
Set parameter for Join Tool
  • Joins crosswalk table to census tracts

61
Model steps
  • Add Join
  • Dissolve
  • Remove join

62
Finished model
63
Summary
  • Attribute extraction
  • Feature location extraction
  • Location proximities
  • Geoprocessing tools
  • Model builder
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